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Updated: May 26, 2026

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water
Published on: August 2, 2012
Effect of NaCl additive on properties of aqueous PEG-sodium sulfate two-phase system
Luisa A Ferreira1, Pier Parpot, José A Teixeira
1IBB - Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal. laferreira@deb.uminho.pt
Abstract:
The concentrations of all components in the phases of aqueous two-phase polyethylene glycol-sodium sulfate system of a fixed composition with different concentrations of NaCl additive were determined. Solvatochromic solvent features of aqueous media in the phases of all the systems were characterized in terms of solvent dipolarity/polarizability, solvent hydrogen bond donor acidity and hydrogen bond acceptor basicity. Partitioning of a homologous series of dinitrophenylated amino acids with aliphatic alkyl side chain was examined in all the systems, and the differences between the relative hydrophobicity and electrostatic properties of the phases were quantified. These differences were described in terms of solvatochromic solvent features of the phases. The previously reported partition coefficients of twelve different nonionic compounds in all the systems were expressed in terms of solute descriptors. It is demonstrated that two solvatochromic solvent descriptors (solvent dipolarity/polarizability, and solvent hydrogen bond donor acidity) could adequately describe the partitioning of the solutes in all the systems employed.
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